Here is an amino acid. The name comes from the fact that this molecule has an amino group (in red) and an acid group (in blue). Anything that has both is an amino acid. In between the "amino" and the "acid" groups are some number of carbon atoms (C) bearing hydrogen atoms (H). The "R" in the structure means that there can also be attached some other random groups, but no matter what that R is, you've still got an amino acid. An interesting aspect of most amino acids is that they exist in left and right handed forms, and this is called chirality. Life on Earth is made of left handed amino acids, and this may be a result of how these molecules formed in space. Click here to learn more.